Conventionally, as shown in FIG. 2, for this type of display method, a hierarchical structure is graphically displayed using what is termed a "tree display". That is, the higher layers are arranged on the upper part of the screen, and the lower layers are arranged on the lower part of the screen. For example, in a communication network, generally, when there are connection relationships between nodes on the same layer, as is shown in FIG. 3, the nodes are arranged on the screen using a plane to show the one layer, and by connecting the nodes with links, the hierarchical structure is displayed.
However, when displaying a hierarchical structure on the display screen of a computer using, for example, this kind of tree display, the problem arises that when the numerous lower layer nodes are arranged on the lower part of the screen, the number of nodes that can be displayed is restricted because of the limitation of the display area. In addition, the problem arises that when displaying, for example, a large scale hierarchical structure having hundreds or thousands of nodes, the lower nodes of the same layer in particular will frequently overlap, and it is difficult to distinguish the links connecting the nodes. Additionally, manipulating the nodes and links on the screen by direct command becomes difficult. In particular, in the case of a complex hierarchical structure having connection relationships between nodes on the same layer, or lower layer connection nodes having a connection relationship with a plurality of upper layer nodes, the ease of viewing and the operability are seriously degraded.
The object of the present invention is to resolve the above-described tree display problems by presenting a method and apparatus for graphic display of multi-layered structures which improves the ease of viewing and operability of large scale hierarchical structures comprising a plurality of nodes on the same screen by spatially arranging the nodes of the same layer using a circles generated according to preset rules.